Ultimate MCQ Quiz: Haloalkanes & Haloarenes 🧪
Topic 1: Classification & Nomenclature
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1. The compound C₆H₅CH₂Cl is an example of a:
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c) Benzylic halide
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2. IUPAC name of CH₃CH(Br)CH₂CH(CH₃)₂ is:
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b) 4-Bromo-2-methylpentane
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3. Which of the following is a gem-dihalide?
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c) 2,2-Dichloropropane
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4. A tertiary alkyl halide is:
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c) 2-Chloro-2-methylpropane
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5. How many chiral carbons are present in 2-Bromo-3-methylpentane?
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c) 2 (at C-2 and C-3)
Topic 2: Methods of Preparation
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6. Best reagent for converting an alcohol to an alkyl chloride is:
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c) SOCl₂ (Darzen's process)
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7. The addition of HBr to propene in the absence of peroxides gives:
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b) 2-Bromopropane (Markovnikov's rule)
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8. Finkelstein reaction is an example of a:
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a) Halide exchange reaction
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9. Sandmeyer's reaction uses which catalyst?
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c) Cuprous halide (CuX)
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10. The reaction of toluene with Cl₂ in the presence of sunlight gives:
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c) Benzyl chloride (Free radical substitution on side chain)
Topic 3: Physical Properties & Nature of C-X Bond
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11. Which compound has the highest boiling point?
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a) n-Butyl chloride (Least branching, largest surface area)
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12. The correct order of boiling points for alkyl halides is:
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b) R-I > R-Br > R-Cl > R-F (Boiling point increases with atomic mass of halogen)
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13. Which of the following has the highest dipole moment?
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b) CH₃Cl (Due to the combined effect of electronegativity and bond length)
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14. The correct order of C-X bond length is:
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a) C-F < C-Cl < C-Br < C-I (Increases with the size of the halogen atom)
Topic 4: Nucleophilic Substitution (Sₙ1 & Sₙ2) & Stereochemistry
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15. The Sₙ1 reaction mechanism involves the formation of a:
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b) Carbocation intermediate
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16. Which of the following is most reactive towards Sₙ2 reaction?
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d) CH₃-Cl (Least steric hindrance)
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17. An Sₙ2 reaction at an asymmetric carbon of a compound always gives:
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c) A product with opposite optical rotation (inversion)
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18. The order of reactivity of alkyl halides in Sₙ1 reaction is:
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b) 3° > 2° > 1° (Based on stability of carbocation)
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19. Racemization occurs in which type of reaction?
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a) Sₙ1 reaction (Due to planar carbocation intermediate)
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20. Which of the following has the best leaving group?
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d) I⁻ (It is the weakest base)
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21. Reaction of ethyl chloride with KCN gives:
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b) Propane nitrile (KCN is ionic, C-C bond forms)
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22. Reaction of ethyl chloride with AgCN gives:
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a) Ethyl isocyanide (AgCN is covalent, attack occurs through N)
Topic 5: Elimination & Other Reactions
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23. Dehydrohalogenation of an alkyl halide is carried out using:
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b) Alcoholic KOH
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24. The major product of the dehydrohalogenation of 2-Bromopentane is:
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b) Pent-2-ene (Saytzeff's Rule - more substituted alkene is major)
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25. Grignard reagent is prepared by reacting an alkyl halide with:
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b) Magnesium in dry ether
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26. Wurtz reaction of methyl bromide with sodium in dry ether gives:
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b) Ethane
Topic 6: Reactions of Haloarenes
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27. Haloarenes are less reactive than haloalkanes towards nucleophilic substitution because of:
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d) All of the above
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28. The reaction of Chlorobenzene with Sodium in dry ether gives Biphenyl. This reaction is called:
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c) Fittig reaction
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29. In electrophilic substitution of chlorobenzene, the chlorine atom acts as:
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c) A deactivating and o,p-directing group
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30. The presence of a -NO₂ group at the ortho position of chlorobenzene ________ the reactivity towards nucleophilic substitution.
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a) increases (due to its electron-withdrawing nature)
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31. Wurtz-Fittig reaction involves:
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c) One molecule of aryl halide and one molecule of alkyl halide
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32. Which of the following is most reactive to electrophilic substitution?
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b) Benzene (Halogens are deactivating)
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33. Dow's process converts chlorobenzene to phenol using:
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b) Aqueous NaOH at 623K and 300 atm